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Housefly Larvae: An Eco-Friendly Alternative to Soy in Animal Feed?

06 July 2016

NETHERLANDS - The animal feed industry is looking for alternatives to environmentally harmful ingredients such as soybean meal and fishmeal, and researchers from Wageningen University are looking into the potential of housefly larvae for this purpose.

“Soy cultivation has had major negative effects such as deforestation, loss of biodiversity and high CO2 emissions, especially in Brazil and Argentina," said Hannah van Zanten, scientist at the Animal Production Systems chair group of Wageningen University.

"Insects are considered an interesting alternative because they do not require much land and can feed on waste.”

Ms Van Zanten studied the environmental effects of the cultivation of housefly larvae for animal feed production in the Netherlands, and concluded that housefly larvae are more eco-friendly per kilo than soy or fishmeal.

However, she also analysed the indirect effects and these make the story much more nuanced.

“In this study we fed the larvae partly with chicken manure and partly with waste. The waste is the problem as 98 per cent is currently being fermented for generating bio-energy. This bio-energy replaces fossil fuels, and so benefits the environment.

"Feeding all this waste to insects would increase the need for fossil fuels, resulting in a negative environmental balance overall.”

Ms Van Zanten modelled these impacts and concluded that it is currently unwise to aim at insect production for animal feed.

If in future, countries like the Netherlands would use more wind and solar energy and less fossil fuels, less waste would be needed to produce biofuels to replace these with, and insect production would become more beneficial.

Ms Van Zanten advocates an integrated approach to achieve sustainable changes in the animal feed sector. “This study proves that a measure in one chain may have unexpected effects in another – positive or negative.”